It is sometimes desirable to reduce unnecessary electric power consumption. Many devices, such as computer monitors, printers, fax machines, scanners, and audio equipment consume power when idle, and some devices consume power even when turned off. Other devices, such as lights, lamps, and other lighting devices, are often left on when not needed, such as when an office or other room is unoccupied for prolonged intervals. Interrupting electric power to electric devices is a way to reduce unnecessary or otherwise undesirable power consumption.
Numerous schemes are used or have been proposed to control a power supply to electric devices. For instance, locally-timed electric power controllers that have integral timers are plugged into electrical outlets, and are set to control power to power outlets over specific time intervals. These interrupters typically require that each device be set or programmed individually. Remote or central management of electric power controllers is often desirable, especially when many power controllers are used at multiple locations.
Remotely or centrally managed power controllers include devices that are managed via signals transmitted through a building's hardwired power distribution system, and controllers that are connected to and managed by a computer. Computer management of power controllers, including management via Ethernet connections, also exists or has been proposed. Typically, centrally or remotely-managed power control devices participate in information exchange with a central computing or other information processing or distribution source. These centrally managed power control devices require that relatively sophisticated information processing and exchange capability reside in each device.
One remotely managed power interruption device that does not require information exchange is disclosed in U.S. Pat. No. 6,744,150 ('150), which describes a power strip that energizes or de-energizes power strip outlets based on a five volt power tap on a computer. If a signal is received from the tap, which indicates the computer is running, the power strip would continue to supply power to its plugged-in devices. However, power synchronization between an interrupter and a controlling computer is undesirable because it is often desirable for computers to remain turned on continuously or for multi-day intervals. For instance, computers often need to remain powered throughout the night in order to receive network updates or run various applications that require significant CPU resources not available during normal working hours. The '150 reference discloses a power controller that interrupts power if, and only if, the controlling computer is turned off. Thus the prior art disclosed in '150 suffers from very primitive power management capability.
Ethernet technology, and digital signal technology generally, given its pervasive use in both commercial and residential applications combined with the highly programmable nature if its network elements provides a powerful way to manage electric power consumption. For instance, Ethernet switches have been used for remote or central control of power interrupters or controllers. However, existing Ethernet-managed power controllers engage in two-way communication with Ethernet switches and require processors for interpreting Ethernet signals and communicating with the Ethernet switches. See U.S. Pat. No. 6,507,273 ('273), U.S. Pat. No. 7,171,461 ('461), U.S. Pat. No. 6,445,087 ('087), and U.S. Pat. No. 6,744,150 ('150), as well as U.S. Pat. App. 2005/0052817 ('817).
The '273 reference describes a power controller that communicates with a remote computer via Ethernet, Internet, or other network connection, in part by sending a remote control program to the remote computer. The '817 and '461 references also disclose systems that have two-way communication with a remote computer. Thus existing power controlling devices require that information processing and two-way communication capability reside in the controllers themselves in order to achieve relatively sophisticated remote or central management of the power controllers. Consequently, there remains a need for a simplified device that can control power consumption by utilizing the many advanced features and sophisticated functionality existing in existing managed network devices, such as but not limited to Ethernet switches and routers.